A magistrate in the 18th century in Sheppey, Kent, John Sawbridge developed a signalling system using pigeons. Smugglers would sail to a nearby ship wreck, and dump any booty they found into the sea. They would then release homing pigeons which flew direct to Sir John to notify him. When the tide carried the goods ashore, the good magistrate would be there to meet and collect it, before the customs officers knew anything about it.